Prior to shipment of semiconductor components such as LSIs and ICs, a semiconductor test of supplying power to the semiconductor component to take out a signal, and checking operation of the semiconductor component is carried out. In a semiconductor test, it is common to use a test machine having a socket board in which a power supply board and a signal leading board are superposed on each other, and a socket in which probes penetrate in a resin casing. In the semiconductor component and the socket board, signal leading electrode pads (signal pads, hereinafter) and power supply electrode pads (power pads, hereinafter) are arranged, the socket is mounted on the socket board. A semiconductor component is mounted on the socket so that electrode pads of the semiconductor component and the socket board are electrically connected to each other through a probe of the socket.
In recent years, leakage current is increased by finer design rules of a semiconductor component and power source frequency is increased by speedup tendency of a server apparatus or the like on which the semiconductor component is mounted. Accordingly, an amount of current in the semiconductor component at the time of operation is increased. The power consumption in the past was at most about 50 [W] but now it exceeds 100 [W]. In addition, data bus width of a server apparatus is expanded. Accordingly, a ratio of signal pads to the entire electrode pads is increased and a ratio of power pads is reduced. Thus, an amount of current flowing through one power probe which connects power pads of the semiconductor component and the socket board is abruptly increased. Since the probe is surrounded by a resin casing, it may not radiate heat easily, and if the heating value increases as the current increases, a pressure spring which presses the probe against the electrode pad may be damaged.
In this regard, it is common that a socket is provided with a blower fan or a heat sink to efficiently radiate heat generated by the probe. There is also proposed a technique in which an power supply board embedded with a signal leading line therein is provided with a through hole and plated with gold on the inner wall. A contact pin is inserted into the through hole, and an elastic material is pushed against the semiconductor component, thereby causing the board and the contact pin to contact directly with each other (see Japanese Patent Laid-open Application No. 2001-13208, for example). According to this technique, it is possible to shorten a current path between the power supply board and contact pin, reducing a resistance so that the heating value is suppressed.
According to the technique, however, since the signal leading line is embedded in the power supply board, if the number of signal leading lines is increased, the circuit becomes complicated. Thus, although this socket can be applied to a high temperature testing socket of a semiconductor component, there is a problem that it is difficult to use this socket as a normal socket which is mounted on a server apparatus and used for connecting a semiconductor component and an external component with each other.